The reason I would go for the A6400 is the425 point auto focus which on the you tube videos Ive seen looks amazing
It is very good, but what do you need it for? In other words, what kinds of things are you planning to take photos of?
My 'Travel' camera is the A6000, with the 16-50, 55-210 and 50 f/1.8 lenses.
I have looked at the A6400 as a possible upgrade, and the improved EVF and AF look appealing, but I'm not convinced the A6400 is worth an extra £550 - over twice the price of an A6000.
The biggest weakness of the A6xxx cameras is the lens options - you have the Sony 35 and 50 f/1.8 OSS primes, both of which are nice, and a number of decent Sigma primes (but they lack OSS). There are no 'high quality' APS-C zooms (though you can always use FF E mount zooms - but the best are large, heavy and expensive).
The 16-50 and 55-210 kit zooms are actually quite good for what they are - cheap, small and light - capable of producing very good images provided you are aware of their limitations (the 16-50 has no lens hood, and is quite susceptible to flare, for example).
Below is one I took with my A6000 - using the 16-50 kit lens, handheld.
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FWIW I wouldn't recommend you jump in with Full Frame camera any more than I'd suggest someone learned to drive in a Ferrari.It takes a while before your gear will limit you more than your skills and technique.
Sure you may discover a deep passion for photography and quickly grow into the camera or you may discover it's hard work and then the camera just gathers expensive dust.
I'd pop into a proper camera shop if you can and try out the cameras you're thinking of.
I'd also recommend to anyone buying used from a reputable source - most camera shops have used stock (even Jessops sell through CameraJungle online).
Camera gear is generally quite reliable and if you decide to abandon the hobby or change up then you lose a lot less reselling used gear.
TBH I have no issue with people going straight into FF, after all I grew up with 35mm film in which case we didn't really have a choice data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7 However, they really need to know why they want FF and not wrongly assuming that FF will automatically give them the best images. As we've discussed already m4/3 and APS-C can give just as good images when viewed at normal viewing sizes.
The only advantages of FF in this day and age are better noise handling, more shallow DOF (although this can also work against you), and depending on what bodies you are comparing to, better dynamic range.
But again this depends on what you're comparing. For example, the Canon 5D-II is still a top FF camera in terms of the images it can produce, yet the EM1-II has comparable noise handling (and less colour shift) and better dynamic range. No one would 'scoff' at someone shooting with a Canon 5D-II, in fact people would 'marvel' at the images it produces. I know it's different age tech, but my point is a lot of the photography world would praise the images from the 5D-II yet diss the ones from m4/3 data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
The thing about film was even the most complex cameras had very few controls - focus, aperture, shutter speed and iso controlled by what film you loaded data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
The only feedback you got was the focusing split view in the prism and the light meter then a wait for your prints.
I’d caution against going in with a full frame body as there are so many ways to get the control wrong. Even quite modest bodies can be overwhelmingly complicated.
I know all cameras have auto modes but you don’t want to be stuck on auto because the leap to A, S & M is so great you never get a decent result.
A FF sensor has a great capacity to give you razor thin sharp focus but if that’s on the back of your subjects ear and their eyes are blurred you won’t be delighted with the results.
Of course the OP can make their own choice but I really would liken it to learning to drive. You’ll learn the basics of clutch control better in a Ford Fiesta than an Aston trying to get to grips with launch control when you just need a hill start data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
Once you know how to handle the basics then you can step up and enjoy the extra toys.
I see your point, but that is not a full frame vs smaller format thing (except the DOF), but more a feature set. Granted as FF cameras are more geared towards the enthusiasts and pros they do tend to be more feature packed than entry level cameras, although as you say you can have it in full auto and semi auto until you get familiar with it. Also, it depends on what you're looking at. The 'entry level' Olympus EM10 is pretty feature packed and can confuse even the most proficient of us. Something like the Nikon D750 is much easier (imo) to get to grips with. And don't get me started on the Sony controls and menus again data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
I guess we will all have different opinions, but I don't necessarily think high end cameras are any more difficult to learn on. You still need to learn the basics, such as the exposure triangle, metering, when to use s-af and when to use c-af etc. As long as you stay away from the all the bells and whistles initially it's pretty much the same data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
The more videos I watch I'm leaning towards the A7iii, the way I see it is I can stick it auto and give it a try and then gradually build up my knowledge in manual mode.
I think I'll pick it up when I go to the US in May
TBH I don't think you'll be happy unless you do data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7 You never answered the question as to what you intend to shoot? Also, what lenses would you get with it?
Honestly a bit of everything, Vacations, go to Disney a lot and NYC. Will also go to a couple of American car shows